Motorcycle trailer

ABSTRACT

A trailer for a motorcycle including a hitch formed of two parallel flat plates attached to the trailer by a hinge having a transversely disposed horizontal axis. Another flat plate is sandwiched between the two parallel plates and the plates are fastened together by a pin inserted through holes in the plates to form a hinge having a vertical axis. Tubular members are mounted to the motorcycle and receive extensions adjustably mounted to the inner flat plate to thereby attach the trailer to the motorcycle. The trailer also has a resilient suspension system for the trailer road wheel which is adjustable to compensate for various loads carried on the trailer and is formed in a manner such that wind acting on the top of the trailer acts to urge the trailer downwardly to thus stabilize the trailer when in use.

RELATIONSHIP TO OTHER APPLICATIONS

This application is a divisional of Ser. No. 360,635 filed May 16, 1973now U.S. Pat. No. 3,937,489 issued Feb. 10, 1976.

BACKGROUND OF THE INVENTION

I. FIELD OF THE INVENTION

The invention relates to trailers to be towed behind two wheeledvehicles, especially those trailers having a single road wheel. Inparticular, the invention pertains to such a trailer provided with anovel hitch member to attach the trailer to a motorcycle, a noveladjustable trailer road wheel suspension system and means for urging thetrailer downwardly while in use.

II. DESCRIPTION OF THE PRIOR ART

There are a number of prior art trailers adapted to be towed behind amotorcycle. One such prior art trailer incorporates a joint connectingthe frame of the trailer with the towing motorcycle which includes twohinge axes, one of which is inclined upwardly and forwardly with respectto the road surface and the other of which is normally horizontal andalso is perpendicular to the inclined hinge axis. In this device, whenthe towing motorcycle tilts as it does when in a turn, the forcestransmitted to the trailer, which cause it to tilt with the motorcycle,are transmitted to and carried by the hinges of the joint connecting thetrailer frame to the towing motorcycle. Depending on the weight beingcarried by the trailer, these forces could readily cause a distortion ofthe hinges, thus causing them to bind and thereby limiting their freepivoting movement about their axes, and in severe cases breaking thehinge.

Another prior art trailer includes a hitch incorporating two mutuallyperpendicular spindles, one spindle being disposed in the transversehorizontal plane of the trailer and the other being disposed in avertical longitudinal plane of the trailer. Again, when the towingmotorcycle is tilted from the vertical, as it will be in making a turn,the forces transmitted to the trailer to cause it to tilt with themotorcycle are carried entirely by the spindles. These forces can begreat enough to deform the spindles, causing them to bind or even break.

A further prior art trailer includes a suspension system which iscomprised generally of coiled springs disposed between a trailer bed anda frame upon which the trailer road wheel is mounted. These springs areillustrated as coil springs which are oriented to act as compressionsprings, i.e. they are loaded in the direction of their longitudinalaxes.

Yet another prior art trailer teaches a road wheel suspension systemhaving the road wheel mounted at one end of an arm, the arm beingpivotally mounted between its ends to a frame of the trailer, and a coilspring disposed between the other end of the arm and the trailer frame.Again, the coil spring is deformable along its longitudinal axis by theforces being applied to it by the arm.

Further, none of these prior art trailer suspension systems areadjustable.

No prior art trailer known to me provides the combination and attributesof the present invention, viz. a trailer having a simple, inexpensivehitch member which transmits the forces from the towing motorcycle tothe trailer to cause the trailer to follow the maneuvers of the towingmotorcycle without transmitting these forces to the hinge of the hitchand provides a trailer road wheel suspension system which is adjustableto provide various suspension system spring rates to accommodate variousweights carried by the trailer. The trailer is also formed to utilizewind forces generated as the motorcycle is moving to urge the trailerdownwardly and to thereby aid in keeping the trailer from bouncing andskipping about as it is being towed at high speeds or in high winds.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a trailer hitch having two spaced apartflat plates connected to a trailer by a hinge having a transverselydisposed horizontal axis. A single flat plate is slidably receivedbetween the two parallel flat plates and each of the flat plates has ahole disposed therethrough to receive a pin which forms a hinge having avertical axis. Means are provided for removably attaching the trailerincluding the hinge assembly formed by the flat plates, to a motorcycle.When the motorcycle tilts, as it will when making a turn, the flatplates coact with each other to apply a force to the trailer to cause itto tilt in the same direction and to the same degree as the motorcyclebut without applying a force to the pin forming the hinge. A two pointtubular connection is provided between the hinge plates and themotorcycle. This combinaton provides sufficient rigidity and strength toprovide a good connection between the motorcycle and the trailer whilethe plates in combination with the vertical hinge provide a meanspermitting the trailer to bank with the motorcycle while still followingthe motorcycle as it is turning.

In addition, the trailer is equipped with an adjustable trailer roadwheel suspension system which allows the spring rate of the suspensionsprings to be adjusted according to the weight being towed on thetrailers. The suspension system includes a support having a hingetransversely disposed, having a horizontal axis and a pre-loadableadjustable torsion spring operatively associated with this rear wheeltransversely disposed hinge axis. Furthermore the body of the trailer isdesigned to translate the substantially horizontal wind forces to avertical force against the top of the trailer to thereby urge thetrailer downwardly against the road.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the present invention is illustrated in theaccompanying drawings, wherein like numerals refer to like partsthroughout the several views, and in which:

FIG. 1 is a perspective view of a motorcycle having a trailer of thepresent invention attached behind it;

FIG. 2 is a side elevational view of the trailer of FIG. 1 incorporatingthe hitch and adjustable trailer road wheel suspension system of thepresent invention;

FIG. 3 is a rear elevational view of the trailer of FIG. 2;

FIG. 4 is a top exploded view of the hitch of the present invention;

FIG. 5 is a perspective view of a trailer frame incorporating the hitchand suspension system of the present invention;

FIG. 6 is a perspective view of the suspension system of the presentinvention;

FIG. 7 is an enlarged fragmented perspective view of a portion of thesuspension system illustrated in FIG. 6;

FIG. 8 is a sectional view of the trailer hitch taken substantiallyalong line 8--8 of FIG. 5; and

FIG. 9 is a side view partially in section of the adjustable mountingmeans to attach a portion of the trailer hitch to a motorcycle.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIG. 1, the present invention provides a trailerhitch, generally indicated at 10, for attaching a trailer, generallyindicated at 12, to a motorcycle 14.

As can be seen in FIG. 2, the trailer 12 includes a frame 16 and a roadwheel 18. The trailer also incorporates an adjustable trailer road wheelsuspension system, generally denoted at 20. The structural attachment ofthe hitch 10 to the motorcycle 14 is schematically illustrated at 22.

FIG. 3 shows a rear view of the trailer 12 and the adjustable suspensionsystem 20.

Now with reference to FIGS. 4 and 5, the trailer hitch 10 comprises ahinged section formed by two components. The first component is a firstflat plate 24 and the second component is formed of two parallel spacedapart second and third flat plates 26, 28, respectively, which areattached to one end of the trailer frame 16. The second and third flatplates 26, 28 define a space 30 therebetween which slidably receives thefirst flat plate 24. The first flat plate 24 has a hole 32 therethroughgenerally perpendicular to its major flat surfaces, and each of thesecond and third flat plates 26, 28 also has a hole 34, 36 respectively,therethrough generally perpendicular to its major flat surfaces. Inaddition, the holes 34, 36 are coaxial with each other. A bolt 37 isreceived through the hole 32 and holes 34, 36 to connect the first flatplate 24 to the second and third flat plates 26, 28, thus forming ahinge having a vertically disposed axis about which the first and secondcomponents of the hitch 10 can pivot.

The hitch 10 further comprises symmetrical attachment means, generallydenoted as 40 adjustably attached to the motorcycle on opposite sidesthereof. With reference to FIGS. 4, 8 and 9, the attachment means 40includes two spaced apart elongated first members, such as hollow tubes42, which are fixed to bracket members 43 which in turn are eachadjustably attached to one end to the first flat plate 24 by bolt 56,and two elongated second members, such as hollow tubes 44, which areeach adjustably attached at one end to the motorcycle 14 on oppositesides thereof. The other end of each of the hollow tubes 42 isadjustably attached to a different one of the hollow tubes 44 near theirother ends. The components of the attachment means 40 associated withthe opposite sides of the motorcycle 14 and the first flat plate 24 areidentical and are referred to by like numerals. While the followingdescription refers to one hollow tube 42 and one hollow tube 44 on oneside of the motorcycle 14 for clarity, it holds true with reference toboth tubes 42 and both tubes 44 also.

As can best be seen in FIG. 9, the hollow tube 44 includes holes 48defined therethrough along its longitudinal axis, and the hollow tube 42includes holes 46 defined therethrough along its longitudinal axis. Thehollow tube 42 axially slidably receives therein the hollow tube 44. Theholes 46 in hollow tube 42 and the holes 48 in hollow tube 44 removablyreceive a hitch pin 50 to connect the tubes 42 and 44 together. The tube44 could, of course, be a rod or it could receive the tube 42.

As can best be seen in FIG. 1, the hollow tube 42 is mounted to themotorcycle by a bracket 51 (FIG. 9) which is mounted to the frame of themotorcycle under or near the seat by a bolt 53 and by a shock absorberbolt 55. The trailer 12 is mounted to the motorcycle 10 by attaching thetubes 42 and 44 together.

As can best be seen in FIG. 4, a slotted hole 52 is defined in the firstflat plate 24 generally transversely to the longitudinal axis of thetrailer and a hole 54 is defined in the bracket 43 attached to thehollow tube 42. The bolt 56 is received through the slotted hole 52 inthe first flat plate 24 and the hole 54 in the bracket 43 to adjustablyconnect them together. This permits accommodation of motorcycles ofdifferent widths.

FIGS. 5 and 8 illustrate the attachment means of the second and thirdplates 26, 28 to one end of the trailer frame 16 (FIG. 5). Thisattachment means includes a hinge 58 pivotally affixed to the trailerframe 16, with its pivotal axis horizontally disposed and transverse tothe longitudinal axis of the trailer. The hinge 58 is affixed to thesecond and third flat plates 26, 28. The hinge 58 includes atransversely disposed tube 60 affixed to the trailer frame 16, and ahollow tube 62 which axially and rotatably receives the tube 60. Thesecond flat plate 26 and third flat plate 28 are attached as by weldingto the hollow tube 62. The hinge 58 allows the second and third flatplates 26, 28 to arcuately pivot about the axis of the hinge in thevertical longitudinal plane of the trailer frame as indicated on theline A--A of FIG. 8.

As can be best seen in FIGS. 5, 6 and 7 the adjustable trailer roadwheel suspension system 20 for resiliently mounting the trailer roadwheel 18 to the trailer is located at the other end of the frame 16 fromthe hitch 10. The road wheel 18 is rotatably mounted to one end of asupport 64. The support 64 is operatively affixed at its other end to aswing arm 68 pivotally affixed to the trailer frame 16, with its axis ofrotation horizontally disposed transversely thereto so that the roadwheel 18 can pivot in the vertical longitudinal plane of the trailerframe. The swing arm 68 includes a transversely disposed rod 70 affixedto the trailer frame 16, as by bolts (not shown) and a hollow tube 72which axially and pivotally receives the rod 70. The support 64 isattached to the hollow tube 70 as by, for example, welding. Theresilient components of the trailer road wheel suspension system 20include two torsion springs 74, each axially disposed over opposite endsof the swing arm 68. First and second restraining means are associatedwith each of the torsion springs 74. Because each torsion spring 74 andthe first and second restraining means associated with each torsionspring are identical and are referred to by like numerals, the followingdescription refers to one torsion spring 74 and its associated first andsecond restraining means for clarity and also holds true with referenceto both torsion springs 74 and both first and both second restrainingmeans also.

The first restraining means is a transversely disposed bar 76 affixed atits ends to the trailer frame 12 in front of the hinge rod 70 as by, forexample, welding. The second restraining means is a bracket 78 (FIGS.5-6) structurally affixed to the road wheel support 64 as by welding.The bracket 78 includes a plurality of notches 80 defined therein, eachhaving one open end 81. As mentioned above, each torsion spring 74 isdisposed axially over one end of the swing arm 68, with its longitudinalaxis substantially coaxial with the longitudinal axis of the rod 70. Oneend of the torsion spring 74 forms a hook 82 which clampingly engagesthe bar 76 and in so doing is restrained. The other end of the coilspring 74 forms a tang 84 which is selectively received in a selectedone of the notches 80 through its open end 81 in the bracket 78 and isrestrained thereby. The coil spring 74 is torsionally preloaded todifferent selected loads by placing the tang 84 in different selectednotches 80 because the end of the coil spring 74 is restrained. The coilspring 74 is biased in a direction which resists an upward movement ofthe road wheel in relationship to the trailer.

The first plate 24 is adjusted with relationship to the motorcycle 14 bysliding the hollow tubes 42 axially with respect to the hollow tubes 44as best seen in FIG. 9. When the appropriate holes 46 in the tube 42line up with one of the appropriate holes 48 in the tube 44 to producethe desired space between the first flat plate 24 and the motorcycle 14,the pins 50 are inserted through the holes 46, 48 in the hollow tubes42, 44 to connect them together. The elongated slots 52 in the plate 24permit the plate 24 to accommodate motorcycles of different widths.

To hitch the trailer 12 to the motorcycle 14, the tube members 44 aremounted to opposite sides of the motorcycle 10 and after the brackets 43of the tube members 42 have been properly spaced on the flat plate 24 bymeans of the slots 52, the tube members 42 are inserted over the tubemembers 44 and the hinge pins 50 are inserted to lock the tube members42, 44 together. The flat plates 24, 26, and 28 form a connection whichpermits pivotal movement in only the vertical axis. As the towingmotorcycle 14 tilts or leans as it turns, especially during shallow highspeed turns, the hitch 10 of the present invention causes the trailer 12to tilt or lean with the motorcycle by the interaction of the flatplates comprising the hitch 10 while allowing the trailer to pivot aboutthe hitch. As the motorcycle 14 leans, the first flat plate 24 bearsagainst the second and third flat plates 26, 28 transmitting a forcethereto which causes the trailer 12 to lean with motorcycle 14. Thehitch 10 leaves the bolt 37, comprising the vertical hinge axis, free ofthose forces generated in the hitch which cause the trailer to lean withthe motorcycle. If these forces were transmitted to the bolt 37, theycould distort it, causing a binding between the bolt 37 and hitch 10 andpreventing the trailer from pivoting about the hitch.

In addition, the hinge 58 with its transversely disposed horizontal axisallows the trailer and the motorcycle 14 to move relative to each otherin the longitudinal vertical plane of the trailer as the motorcycle andtrailer travel over undulating terrain.

The trailer road wheel suspension system can be adjusted to producedifferent predetermined spring rates of the torsion springs 74 to suitdifferent weights carried on the trailer 12 by selectively placing thetang 84 in a different one of the notches 80. Moving the tang 84 fromthe lowermost notch to the higher notches in the bracket 78 requires anincreasingly greater torsional load to be applied to the torsion spring.Because the end of the torsion spring having the hook 82 and the end ofthe torsion spring having the tang 84 are restrained, the torsion spring74 stores this torsional energy. The torsion spring 74, is thus biasedto resist upward movement of the trailer load wheel 18 in the verticallongitudinal plane of the trailer. The greater the weight to be carriedby the trailer, the greater the torsion springs 74 can be preloaded bymerely moving the tang 84 to one of the notches 80 corresponding to agreater torsional loading of the torsion springs.

As can best be seen in FIGS. 1-3, a box 90 is mounted to the frame 16and is provided with a smoothly contoured, generally flat upswept rearportion 92 which acts to utilize the wind forces produced as the traileris being towed to produce a downward force on the trailer. This downwardforce adds considerably to the stability of the trailer and aids inholding it to the road even when unloaded and in relatively high winds.Tail lights 94 are provided on the back of the box 90 and are adapted tobe connected into the lighting system of the motorcycle in theconventional manner. A fender 96 preferably extends outwardly from therear of the box 90 to house a portion of the wheel 18.

Handles 98 are provided on each side of the frame 16 as can best be seenin FIGS. 1, 2, and 5 to aid in moving the trailer about when it is notattached to the motorcycle.

The foregoing detailed description is given primarily for clarity ofunderstanding and no unnecessary limitations should be understoodtherefrom for modifications will be obvious to those skilled in the artupon reading this disclosure and may be made without departing from thespirit of the invention or the scope of the appended claims.

We claim:
 1. A vehicle having a frame, a U-shaped wheel supportstructure comprising a swing arm and a wheel support member extendingfrom each end of said swing arm, a road wheel rotatably mounted betweensaid wheel support members, said swing arm being pivotally mounted tosaid frame for pivotal movement of said wheel support structure about ahorizontal axis, a torsion spring member wrapped around said swing armand having one end attached to a bar extending transversely across andattached to said frame and means for adjustably attaching the other endto said wheel support structure whereby the force exerted by saidtorsion spring with respect to said frame and said wheel supportstructure can be changed by manipulating said adjustable attachingmeans, said adjustably attaching means comprising a bracket attached toone of said wheel support members, said bracket having a plurality ofvertically spaced notches provided therein, the end of said spring beinginsertable in any one of said notches to thereby affix said springbetween said wheel support structure and said frame, the notch selectedfor engagement with the end of said spring determining the torsionproduced by said spring.
 2. A vehicle having a frame, a U-shaped wheelsupport structure comprising a swing arm and a wheel support memberextending from each end of said swing arm, a road wheel rotatablymounted between said wheel support members, said swing arm beingpivotally mounted to said frame for pivotal movement of said wheelsuport structure about a horizontal axis, a torsion spring memberwrapped around said swing arm and having one end attached to a barextending transversely across and attached to said frame and means foradjustably attaching the other end to said wheel support structurewhereby the force exerted by said torsion spring with respect to saidframe and said wheel support structure can be changed by manipulatingsaid adjustable attaching means, said adjustable attaching meanscomprising a bracket having a plurality of notches, said bracket beingattached to one of said wheel support members, the second-mentioned endof said torsion spring forming a tang which is receivable in a selectedone of said notches in said bracket whereby a different torsional forcemust be imparted to said torsion spring to position said tang in each ofsaid notches such that said torsion spring is preloaded to exert apredetermined biasing force.
 3. The vehicle as defined in claim 2,wherein the swing arm comprises a transversely disposed rod structurallyattached to said vehicle frame and a hollow tube coaxially disposedaround said rod so that said hollow tube can rotate about said rod.